You could get an adapter if you wish, although I'm not sure how worthwhile it would be for the 50mm f/1.8. The mirror lens will be hard to focus and use, especially with an adapter. It is effectively an 800mm lens on a T3i from a field of view perspective, with very narrow depth of field as can be seen in my example. Also, you will not have any focus confirm information available through the viewfinder a f/8, even if the adapter has a chip.

Unless you are specifically fond of either of those lenses I would question the value of trying to use them.

You can get a new Canon EF 50mm f/1.8 for $125 with pretty decent optics or the new Yongnuo 50mm f/1.8 Lens for Canon EF for around $65, and some people think it is better than the Canon lens.

Many people on the forum don't like mirror lenses for all sorts of reasons, and many of them are good reasons. I use mine occasionally, only for a few special things. I have a used Canon EF 70-300mm f/4-5.6 IS USM which sees a lot more use.

Good luck with whatever you choose to do.